1. Field of the Invention
This invention relates to electrical switching apparatus, especially such apparatus as power circuit breakers, network protectors and switches used in electric power circuits carrying large currents. More particularly, it relates to indicators in such apparatus which display the open/close state of the switch contacts and the charge/discharge state of the large spring used to close the contacts. Specifically, it relates to such indicators mounted in the face plate of the apparatus.
2. Background Information
Electrical switching apparatus for opening and closing electric power circuits typically utilize an energy storage device in the form of one or more large springs to close the contacts of the device into the large currents which can be drawn in such circuits. Such electrical apparatus includes power circuit breakers and network protectors which provide protection, and electrical switches which are used to energize and deenergize parts of a power circuit or to transfer between alternative power sources.
Typically, such electrical switching apparatus is provided with indicators which display the open/close state of the switch contacts and the charge/discharge state of the close spring. Typically these indicators are flags which bear legends indicating the respective conditions. Often these flags are mounted on the operating mechanism and are visible through openings in the cover of the apparatus. The flag reciprocates between two positions which alternately align the legends indicating the two states with the opening. Manufacturing tolerances often make it difficult to properly align the flags with the openings in the cover.
There is a need, therefore, for improved electrical switching apparatus with indicators for indicating operating states of the apparatus.
More particularly, there is a need for such electrical switching apparatus with improved indicators for indicating the state of the main contacts and/or the state of the closing spring.
There is a further need for such electrical switching apparatus in which the indicators are usually aligned with the openings through which they are viewable.